NI-0801, an anti-chemokine (C-X-C motif) ligand 10 antibody, in patients with primary biliary cholangitis and an incomplete response to ursodeoxycholic acid

Cellular interactions in self-directed immune-mediated liver diseases

The lymphocyte population must traverse a complex path throughout their journey to the liver. The signals which these cells must detect, including cytokines, chemokines and other soluble factors, steer their course towards further crosstalk with other hepatic immune cells, hepatocytes and biliary epithelial cells. A series of specific chemokine receptors and adhesion molecules drive not only the recruitment, migration, and retention of these cells within the liver, but also their localisation. Perturbation of these interactions and failure of self-recognition drive the development of several autoimmune liver diseases. We also describe check point-induced liver injury. Immune cell internalisation into hepatocytes (emperipolesis) in autoimmune hepatitis and into biliary epithelial cells (intra-epithelial lymphocyte) in primary biliary cholangitis are typical features in autoimmune liver diseases. Finally, we describe emerging immune-based therapies, including regulatory T cell, anti-cytokine and anti-chemokine therapies, cytokine supplementation (e.g. interleukin-2), as well as co-inhibitory molecule manipulation, including T-cell engagers, and discuss their potential application in the treatment of autoimmune liver diseases.

A placebo-controlled Phase 2 trial of E6011, anti-human fractalkine monoclonal antibody, in primary biliary cholangitis

BACKGROUND

While ursodeoxycholic acid (UDCA) remains the first-line therapy for primary biliary cholangitis (PBC), the autoimmune nature of PBC underscores the need for treatments targeting immunological pathways that may achieve a cure. E6011, a novel humanized anti-fractalkine monoclonal antibody, has emerged as a potential therapeutic option for PBC. We conducted a randomized, placebo-controlled, double-blind study to evaluate the efficacy and safety of E6011 in patients with PBC with an incomplete response to UDCA.

METHODS

The study was composed of 12-week Double-Blind Phase (placebo, E6011 10 mg/kg/month, 15 mg/kg/month, or 10 mg/kg/every other week [eow]) followed by a 52-week Open-Label Phase. The primary endpoint was the percent change in alkaline phosphatase (ALP) at Week 12.

RESULTS

A total of 29 patients were enrolled. Histological evaluation at screening revealed that 83 % of the enrolled patients were classified as Stage 4 according to the Nakanuma Classification. The mean percent changes in ALP at Week 12 were +0.45 % in the placebo, +0.65 % in the 10 mg/kg/month, +1.23 % in the 15 mg/kg/month and +1.19 % in the 10 mg/kg/eow, with no observed trends toward ALP reduction in the E6011 treatment. Based on the interim analysis, the study was discontinued due to a lack of the efficacy. E6011 was generally safe and well tolerated.

CONCLUSION

This study of E6011 failed to meet the primary endpoint in patients with PBC with an incomplete response to UDCA. The advanced histological severity present in more than 80 % of patients at baseline may have contributed to these findings.

Soluble Herpes Virus Entry Mediator and Type II/III Interferons Are Upregulated in Primary Biliary Cholangitis

Bacterial translocation-induced inflammation and immune dysfunction are recognised factors contributing to the pathogenesis of primary biliary cholangitis (PBC). However, the specific involvement of interferons (IFNs) and soluble checkpoints (sol-CRs) in shaping the immune landscape in PBC patients remains unexplored. Furthermore, the influence of ursodeoxycholic acid (UDC) on these immune mediators is unknown. Twenty-eight cytokines and 14 sol-CRs were quantified by Luminex assays in plasma samples from 64 PBC patients and 10 healthy controls (HCs). D-lactate was measured as a marker of bacterial translocation. The PBC subgroups were: 24 UDC responders (UDCRs), 18 UDC non-responders (UDCNRs) and 22 patients with end-stage cirrhotic PBC (ESPBC). Soluble herpes virus entry mediator (HVEM) was upregulated in the UDCR subgroup compared to the HC group (p = 0.0404), with increased significance in the ESPBC subgroup (p < 0.0001). There was a progressive increase in several sol-CRs, particularly soluble CD80, LAG3 and CD137 in ESPBC patients. IFN-gamma was higher in the ESPBC subgroup compared to the UDCR subgroup. Elevated IFN-gamma in the UDCNR subgroup compared to UDCR was more significant on excluding patients with cirrhosis (p = 0.0056). Patients with ESPBC expressed several pro-inflammatory cytokines including IL-6, TNF-alpha and CXCL10 compared to the HC group. IFN-lambda-3, but not IFN-lambda-2, was elevated in the ESPBC subgroup compared to all other subgroups. D-lactate levels were equally elevated in all PBC subgroups compared to the HC group. This study provides valuable insights into the immune landscape of PBC, highlighting potential biomarkers and cytokine signatures associated with disease severity and treatment response. Further investigation into the mechanistic roles may pave the way for more targeted therapeutic interventions in PBC management.

Probing the Effects of Multisite Mutations in the Lipoic Acid Region of the BCOADC-E2 Protein

Primary biliary cholangitis (PBC) is a chronic disease, the prevalence of which has been increasing in recent years. And the prevalence of patients who test negative with existing diagnostic techniques remains high. It was found that the antigenic BCOADC-E2 protein could detect patients with a negative original test. And experiments revealed that the lipoyl domain of BCOADC-E2 plays an important role. The present study was carried out to verify the necessity of maintaining the folding conformation of the lipoyl β-sheet of the protein in the lipoyl domain during the recognition of the BCOADC-E2 protein and the importance of the glutamic acid and isoleucine residues at position 4 and position 13, respectively. In order to search for a new pathway for the pre-detection of patients with PBC, firstly, the mutant proteins were subjected to an enzyme-linked immunosorbent assay (ELISA) with serum. Then, MTSSL spin tags were positioned at specific sites of the Cys mutant and reacted with serum samples from PBC patients and controls, and EPR spectroscopic data were measured. The multiple mutant proteins all reacted less specifically with the serum than the wild-type protein in the ELISA; the spectra measured for the pGEX-BCKD-E4A-I13A mutant were severely broadened, and the compactness at the conformational position of the lipoyl β-sheet structural conformation of the proteins of amino acids 4 and 13 remained unchanged. The EPR spectral data validate the importance of the glutamate and isoleucine residues at position 4 and position 13 and their necessity in the maintenance of the lipoyl β-sheet structural conformation of proteins in the lipoyl domain in anti-BCOADC-E2 recognition.

Immunopathogenesis of Primary Biliary Cholangitis, Primary Sclerosing Cholangitis and Autoimmune Hepatitis: Themes and Concepts

Autoimmune liver diseases include primary biliary cholangitis, primary sclerosing cholangitis, and autoimmune hepatitis, a family of chronic immune-mediated disorders that target hepatocytes and cholangiocytes. Treatments remain nonspecific, variably effective, and noncurative, and the need for liver transplantation is disproportionate to their rarity. Development of effective therapies requires better knowledge of pathogenic mechanisms, including the roles of genetic risk, and how the environment and gut dysbiosis cause immune cell dysfunction and aberrant bile acid signaling. This review summarizes key etiologic and pathogenic concepts and themes relevant for clinical practice and how such learning can guide the development of new therapies for people living with autoimmune liver diseases.

Ursodeoxycholic acid and 18β-glycyrrhetinic acid alleviate ethinylestradiol-induced cholestasis via downregulating RORγt and CXCR3 signaling pathway in iNKT cells

Estrogen-induced intrahepatic cholestasis (IHC) is a mild but potentially serious risk and urges for new therapeutic targets and effective treatment. Our previous study demonstrated that RORγt and CXCR3 signaling pathway of invariant natural killer T (iNKT) 17 cells play pathogenic roles in 17α-ethinylestradiol (EE)-induced IHC. Ursodeoxycholic acid (UDCA) and 18β-glycyrrhetinic acid (GA) present a protective effect on IHC partially due to their immunomodulatory properties. Hence in present study, we aim to investigate the effectiveness of UDCA and 18β-GA in vitro and verify the accessibility of the above targets. Biochemical index measurement indicated that UDCA and 18β-GA presented efficacy to alleviate EE-induced cholestatic cytotoxicity. Both UDCA and 18β-GA exhibited suppression on the CXCL9/10-CXCR3 axis, and significantly restrained the expression of RORγt in vitro. In conclusion, our observations provide new therapeutic targets of UDCA and 18β-GA, and 18β-GA as an alternative treatment for EE-induced cholestasis.

New Therapies on the Horizon for Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease that can progress to cirrhosis and hepatic failure if left untreated. Ursodeoxycholic acid (UDCA) was introduced as a first-line drug for PBC around 1990; it remarkably improved patient outcomes, leading to the nomenclature change of PBC in 2015, from primary biliary "cirrhosis" to primary biliary "cholangitis." Nevertheless, 20-30% of patients exhibit an incomplete response to UDCA, resulting in significantly worse outcomes compared to those with a complete response. Therefore, improving the long-term outcomes of patients with an incomplete response to UDCA has been recognized as an unmet need. In addition, patients with PBC often suffer from a variety of debilitating symptoms, such as pruritus, fatigue and sicca syndrome, which significantly impair their health-related quality of life. Thus, appropriate management of these symptoms is currently regarded as another unmet need for PBC treatment. In this review, several compounds and drugs under clinical trials that can potentially solve these unmet needs are comprehensively discussed, and future directions of treatment policy of PBC are proposed for significantly improving long-term outcome as well as health-related quality of life of patients.

Current Therapies for Cholestatic Diseases

Cholestasis is a condition characterized by decrease in bile flow due to progressive pathological states that lead to chronic cholestatic liver diseases which affect the biliary tree at the intrahepatic level and extrahepatic level. They induce complications such as cirrhosis, liver failure, malignancies, bone disease and nutritional deficiencies that merit close follow-up and specific interventions. Furthermore, as those conditions progress to liver cirrhosis, there will be an increase in mortality but also an important impact in quality of life and economic burden due to comorbidities related with liver failure. Therefore, it is important that clinicians understand the treatment options for cholestatic liver diseases. With a general view of therapeutic options and their molecular targets, this review addresses the pathophysiology of cholangiopathies. The objective is to provide clinicians with an overview of the safety and efficacy of the treatment of cholangiopathies based on the current evidence.

Primary Biliary Cholangitis: Promising Emerging Innovative Therapies and Their Impact on GLOBE Scores

Primary biliary cholangitis (PBC), previously referred to as primary biliary cirrhosis, is an autoimmune disorder leading to the destruction of intra-hepatic bile ducts. If untreated, progressive bile duct damage and cholestasis can lead to ductopenia and result in cirrhosis. Ursodiol, the first drug approved for PBC, has changed the natural history of this disease and improved patient outcomes. Subsequently, several new prediction models incorporating a response to ursodiol were developed. These include the GLOBE score, which was shown to predict long-term outcomes in patients with PBC. In 2016, obeticholic acid (OCA) became the second drug to be approved by the FDA, predominantly based on improvement in alkaline phosphatase (ALP) levels. This trial has subsequently influenced the design of clinical trials. Several drugs are currently being evaluated as therapeutic options for PBC, with improvement in ALP being a main endpoint. In this review, we will discuss the impact of new therapies on GLOBE scores in patients with PBC.

Mechanism-based target therapy in primary biliary cholangitis: opportunities before liver cirrhosis?

Primary biliary cholangitis (PBC) is an immune-mediated liver disease characterized by cholestasis, biliary injuries, liver fibrosis, and chronic non-suppurative cholangitis. The pathogenesis of PBC is multifactorial and involves immune dysregulation, abnormal bile metabolism, and progressive fibrosis, ultimately leading to cirrhosis and liver failure. Ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) are currently used as first- and second-line treatments, respectively. However, many patients do not respond adequately to UDCA, and the long-term effects of these drugs are limited. Recent research has advanced our understanding the mechanisms of pathogenesis in PBC and greatly facilitated development of novel drugs to target mechanistic checkpoints. Animal studies and clinical trials of pipeline drugs have yielded promising results in slowing disease progression. Targeting immune mediated pathogenesis and anti-inflammatory therapies are focused on the early stage, while anti-cholestatic and anti-fibrotic therapies are emphasized in the late stage of disease, which is characterized by fibrosis and cirrhosis development. Nonetheless, it is worth noting that currently, there exists a dearth of therapeutic options that can effectively impede the progression of the disease to its terminal stages. Hence, there is an urgent need for further research aimed at investigating the underlying pathophysiology mechanisms with potential therapeutic effects. This review highlights our current knowledge of the underlying immunological and cellular mechanisms of pathogenesis in PBC. Further, we also address current mechanism-based target therapies for PBC and potential therapeutic strategies to improve the efficacy of existing treatments.

Prospects for targeting ACKR1 in cancer and other diseases

The chemokine network is comprised of a family of signal proteins that encode messages for cells displaying chemokine G-protein coupled receptors (GPCRs). The diversity of effects on cellular functions, particularly directed migration of different cell types to sites of inflammation, is enabled by different combinations of chemokines activating signal transduction cascades on cells displaying a combination of receptors. These signals can contribute to autoimmune disease or be hijacked in cancer to stimulate cancer progression and metastatic migration. Thus far, three chemokine receptor-targeting drugs have been approved for clinical use: Maraviroc for HIV, Plerixafor for hematopoietic stem cell mobilization, and Mogalizumab for cutaneous T-cell lymphoma. Numerous compounds have been developed to inhibit specific chemokine GPCRs, but the complexity of the chemokine network has precluded more widespread clinical implementation, particularly as anti-neoplastic and anti-metastatic agents. Drugs that block a single signaling axis may be rendered ineffective or cause adverse reactions because each chemokine and receptor often have multiple context-specific functions. The chemokine network is tightly regulated at multiple levels, including by atypical chemokine receptors (ACKRs) that control chemokine gradients independently of G-proteins. ACKRs have numerous functions linked to chemokine immobilization, movement through and within cells, and recruitment of alternate effectors like β-arrestins. Atypical chemokine receptor 1 (ACKR1), previously known as the Duffy antigen receptor for chemokines (DARC), is a key regulator that binds chemokines involved in inflammatory responses and cancer proliferation, angiogenesis, and metastasis. Understanding more about ACKR1 in different diseases and populations may contribute to the development of therapeutic strategies targeting the chemokine network.

iNKT17 cells play a pathogenic role in ethinylestradiol-induced cholestatic hepatotoxicity

IL-17 is closely associated with inflammation in intrahepatic cholestasis (IHC). Targeting IL-17 ameliorates IHC in mice. Invariant natural killer T (iNKT) cells are predominantly enriched in the liver and they mediate drug-induced liver injury through their secreted cytokines. However, whether iNKT17 cells are involved in ethinylestradiol (EE)-induced IHC remains unclear. In the present study, the administration of EE (10 mg/kg in vivo and 6.25 μM in vitro) promoted the activation and expansion of iNKT17 cells, which contributed to a novel hepatic iNKT17/Treg imbalance. iNKT cell-deficient Jα18-/- mice and the RORγt inhibitor digoxin (20 μg) alleviated EE-induced cholestatic hepatotoxicity and downregulated the IL-17 signalling pathway. In contrast, the co-administration of EE with recombinant IL-17 (1 μg) to Jα18-/- mice induced cholestatic hepatotoxicity and increased the infiltration of hepatic neutrophils and monocytes. Importantly, the administration of IL-17-/- iNKT cells (3.5 × 105) to Jα18-/- mice resulted in the attenuation of hepatotoxicity and the recruitment of fewer hepatic neutrophils and monocytes than the adoptive transfer of wild-type iNKT cells. These results indicated that iNKT17 cells could exert pathogenic effects. The recruitment and activation of iNKT17 cells could be attributed to the high level of CXCR3 expression on their surface. CXCL10 deficiency ameliorated EE-induced cholestatic liver damage, reduced hepatic CXCR3+ iNKT cells and inhibited RORγt expression. These findings suggest that iNKT17 cells play a key role in EE-induced cholestatic liver injury via CXCR3-mediated recruitment and activation. Our study provides new insights and therapeutic targets for cholestatic diseases.

Update on the Pharmacological Treatment of Primary Biliary Cholangitis

Ursodeoxycholic acid (UDCA) is the first-line therapy used for the treatment of PBC. In recent years, new pharmacological agents have been proposed for PBC therapy to cure UDCA-non-responders. Obeticholic acid (OCA) is registered in many countries for PBC, and fibrates also seem to be effective in ameliorating biochemistry alteration and symptoms typical of PBC. Moreover, a variety of new agents, acting with different mechanisms of action, are under clinical evaluation for PBC treatment, including PPAR agonists, anti-NOX agents, immunomodulators, and mesenchymal stem cell transplantation. Since an insufficient amount of data is currently available about the effect of these novel approaches on robust clinical endpoints, such as transplant-free survival, their clinical approval needs to be supported by the consistent improvement of these parameters. The intensive research in this field will hopefully lead to a novel treatment landscape for PBC in the near future, with innovative therapies based on the combination of multiple agents acting on different pathogenetic mechanisms.

Mechanisms and molecules: What are the treatment targets for primary biliary cholangitis?

Treatment of primary biliary cholangitis (PBC) with ursodeoxycholic acid (UDCA) is not always sufficient to prevent progression to hepatic decompensation and/or need for liver transplant. Adjuvant therapy with obeticholic acid may provide additional biochemical improvements in some patients, but it is not well-tolerated by patients with significant itch or advanced cirrhosis. Thus, new and creative approaches to treating patients with PBC are important to identify. This review discusses major potential therapeutic targets in PBC and provides examples of some specific agents currently in development for the treatment of PBC. Targets are broadly classified into those which strive to modify bile, inflammation, cell survival, or fibrosis. In bile, shrinking the size of the bile acid pool or modifying the quality of the bile by making it more hydrophilic or enriched in phosphatidylcholine may ameliorate cholestatic injury. Biliary epithelial cell survival may be extended by fortifying the bicarbonate umbrella or improving cell membrane integrity. Autoimmunity and cholangitis have the potential to be improved via regulation of the immune system. Targeting cytokines, immune checkpoints, and anti-mitochondrial antibodies are examples of a more focused immunosuppression approach. Stem cell therapy and lymphocyte trafficking inhibition are more novel methods of broad immune regulation. Anti-fibrotic therapies are also potentially useful for preventing progression of PBC. The nuclear hormone receptors, farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR) regulate many of these pathways: cholestasis, inflammation, and fibrosis, which is why they are being enthusiastically pursued as potential therapeutic targets in PBC.

The relationship between disease activity and UDCA response criteria in primary biliary cholangitis: A cohort study

BACKGROUND

Uncertainty exists about how best to identify primary biliary cholangitis (PBC) patients who would benefit from second-line therapy. Existing, purely clinical, ursodeoxycholic acid (UDCA) response criteria accept degrees of liver biochemistry abnormality in responding patients, emerging data, however, suggest that any degree of ongoing abnormality may, in fact, be associated with an increased risk of adverse outcomes. This cohort study explores the link between response status, the biology of high-risk disease and its implications for clinical practice.

METHODS

Proteomics, exploring 19 markers previously identified as remaining elevated in PBC following UDCA therapy, were performed on 400 serum samples, from participants previously recruited to the UK-PBC Nested Cohort between 2014 and 2019. All participants had an established diagnosis of PBC and were taking therapeutic doses of UDCA for greater than 12 months. UDCA response status was assessed using Paris 1, Paris 2 and the POISE criteria, with additional analyses using normal liver blood tests stratified by bilirubin level. Statistical analysis using parametric t tests and 1-way ANOVA.

FINDINGS

Disease markers were statistically significantly higher in UDCA non-responders than in responders for all the UDCA response criteria, suggesting a meaningful link between biochemical disease status and disease mechanism. For each of the criteria, however, marker levels were also statistically significantly higher in responders with ongoing liver function test abnormality compared to those who had normalised their liver biochemistry. IL-4RA, IL-18-R1, CXCL11, 9 and 10, CD163 and ACE2 were consistently elevated across all responder groups with ongoing LFT abnormality. No statistically significant differences occurred between markers in normal LFT groups stratified by bilirubin level.

INTERPRETATION

This study provides evidence that any ongoing elevation in alkaline phosphatase levels in PBC after UDCA therapy is associated with some degree of ongoing disease activity. There was no difference in activity between patients with normal LFT when stratified by bilirubin. These findings suggest that if our goal is to completely control disease activity in PBC, then normalisation of alkaline phosphatase and bilirubin should be the treatment target. This would also simplify messaging around goals of therapy in PBC, benefiting both patients and clinicians.

FUNDING

Funding by the UK Medical Research Council (Stratified Medicine Programme) and an independent research grant by Pfizer. The study funders played no role in the study design, data collection, data analyses, data interpretation or manuscript writing.

A systematic analysis of gene-gene interaction in multiple sclerosis

BACKGROUND

For the most part, genome-wide association studies (GWAS) have only partially explained the heritability of complex diseases. One of their limitations is to assume independent contributions of individual variants to the phenotype. Many tools have therefore been developed to investigate the interactions between distant loci, or epistasis. Among them, the recently proposed EpiGWAS models the interactions between a target variant and the rest of the genome. However, applying this approach to studying interactions along all genes of a disease map is not straightforward. Here, we propose a pipeline to that effect, which we illustrate by investigating a multiple sclerosis GWAS dataset from the Wellcome Trust Case Control Consortium 2 through 19 disease maps from the MetaCore pathway database.

RESULTS

For each disease map, we build an epistatic network by connecting the genes that are deemed to interact. These networks tend to be connected, complementary to the disease maps and contain hubs. In addition, we report 4 epistatic gene pairs involving missense variants, and 25 gene pairs with a deleterious epistatic effect mediated by eQTLs. Among these, we highlight the interaction of GLI-1 and SUFU, and of IP10 and NF-[Formula: see text]B, as they both match known biological interactions. The latter pair is particularly promising for therapeutic development, as both genes have known inhibitors.

CONCLUSIONS

Our study showcases the ability of EpiGWAS to uncover biologically interpretable epistatic interactions that are potentially actionable for the development of combination therapy.

The Serum Proteome and Ursodeoxycholic Acid Response in Primary Biliary Cholangitis

BACKGROUND AND AIMS

Stratified therapy has entered clinical practice in primary biliary cholangitis (PBC), with routine use of second-line therapy in nonresponders to first-line therapy with ursodeoxycholic acid (UDCA). The mechanism for nonresponse to UDCA remains, however, unclear and we lack mechanistic serum markers. The UK-PBC study was established to explore the biological basis of UDCA nonresponse in PBC and identify markers to enhance treatment.

APPROACH AND RESULTS

Discovery serum proteomics (Olink) with targeted multiplex validation were carried out in 526 subjects from the UK-PBC cohort and 97 healthy controls. In the discovery phase, untreated PBC patients (n = 68) exhibited an inflammatory proteome that is typically reduced in scale, but not resolved, with UDCA therapy (n = 416 treated patients). Nineteen proteins remained at a significant expression level (defined using stringent criteria) in UDCA-treated patients, six of them representing a tightly linked profile of chemokines (including CCL20, known to be released by biliary epithelial cells (BECs) undergoing senescence in PBC). All showed significant differential expression between UDCA responders and nonresponders in both the discovery and validation cohorts. A linear discriminant analysis, using serum levels of C-X-C motif chemokine ligand 11 and C-C motif chemokine ligand 20 as markers of responder status, indicated a high level of discrimination with an AUC of 0.91 (CI, 0.83-0.91).

CONCLUSIONS

UDCA under-response in PBC is characterized by elevation of serum chemokines potentially related to cellular senescence and was previously shown to be released by BECs in PBC, suggesting a potential role in the pathogenesis of high-risk disease. These also have potential for development as biomarkers for identification of high-risk disease, and their clinical utility as biomarkers should be evaluated further in prospective studies.

Regulation and functional roles of chemokines in liver diseases

Inflammation is a major contributor to the pathogenesis of almost all liver diseases. Low-molecular-weight proteins called chemokines are the main drivers of liver infiltration by immune cells such as macrophages, neutrophils and others during an inflammatory response. During the past 25 years, tremendous progress has been made in understanding the regulation and functions of chemokines in the liver. This Review summarizes three main aspects of the latest advances in the study of chemokine function in liver diseases. First, we provide an overview of chemokine biology, with a particular focus on the genetic and epigenetic regulation of chemokine transcription as well as on the cell type-specific production of chemokines by liver cells and liver-associated immune cells. Second, we highlight the functional roles of chemokines in liver homeostasis and their involvement in progression to disease in both human and animal models. Third, we discuss the therapeutic opportunities targeting chemokine production and signalling in the treatment of liver diseases, such as alcohol-associated liver disease and nonalcoholic steatohepatitis, including the relevant preclinical studies and ongoing clinical trials.

Association of bezafibrate with transplant-free survival in patients with primary biliary cholangitis

BACKGROUND & AIMS

A beneficial effect of bezafibrate (BZF) on symptoms and biochemical features of primary biliary cholangitis (PBC) has been reported in patients with an incomplete response to ursodeoxycholic acid (UDCA), but long-term effects on survival remain unknown. In Japan, BZF has been used as a de facto second-line therapy for PBC since 2000. Herein, we compared the survival rates between patients treated with and those without BZF in a large nationwide Japanese PBC cohort.

METHODS

All consecutively registered patients of this cohort who started UDCA therapy from 2000 onwards and had a follow-up ≥1 year were included. Association between BZF exposure and mortality or need for liver transplantation (LT) was assessed using time-dependent, multivariable-and propensity score-adjusted Cox proportional hazards models. Clinical benefit was quantified using the number needed to treat (NNT).

RESULTS

Of 3,908 eligible patients, 3,162 (81%) received UDCA only and 746 (19%) UDCA and BZF over 17,360 and 3,932 patient-years, respectively. During follow-up, 183 deaths (89 liver-related) and 21 LT were registered. Exposure to combination therapy was associated with a significant decrease in all-cause and liver-related mortality or need for LT (adjusted hazard ratios: 0.3253, 95% CI 0.1936-0.5466 and 0.2748, 95% CI 0.1336-0.5655, respectively; p <0.001 for both). This association was consistent across various risk groups at baseline. The NNTs with combination therapy to prevent 1 additional death or LT over 5, 10, and 15 years were 29 (95% CI 22-46), 14 (10-22), and 8 (6-15), respectively.

CONCLUSIONS

In a large retrospective cohort study of treatment effects in patients with PBC, the addition of BZF to UDCA was associated with improved prognosis.

LAY SUMMARY

The long-term efficacy of bezafibrate (BZF) on liver transplantation (LT) - free survival in patients with PBC and an incomplete response to ursodeoxycholic acid (UDCA) remains to be determined. In this Japanese nationwide retrospective cohort study, the use of UDCA-BZF combination therapy, compared to UDCA alone, was associated with a lower risk of all-cause and liver-related mortality or need for LT. These results indicate that BZF is so far the only drug in PBC to have demonstrated efficacy in improving symptoms, biochemical markers, and long-term outcomes.

Clinical Management of Primary Biliary Cholangitis-Strategies and Evolving Trends

PBC is a chronic progressive autoimmune disorder involving the destruction of intrahepatic small bile ducts, cholestasis, fibrosis, and ultimately cirrhosis if left untreated. It is largely driven by the autoimmune response, but bile acids and the intestinal microbiota are implicated in disease progression as well. The only drugs licensed for PBC are UDCA and OCA. UDCA as a first-line and OCA as a second-line therapy are safe and effective, but the lack of response in a significant portion of patients and inadequate control of symptoms such as fatigue and pruritus remain as concerns. Liver transplantation is an end-stage therapy for many patients refractory to UDCA, which gives excellent survival rates but also moderate to high recurrence rates. The limited options for FDA-approved PBC therapies necessitate the development of alternative approaches. Currently, a wide variety of experimental drugs exist targeting immunological and physiological aspects of PBC to suppress inflammation. Immunological therapies include drugs targeting immune molecules in the B cell and T cell response, and specific cytokines and chemokines implicated in inflammation. Drugs targeting bile acids are also noteworthy as bile acids can perpetuate hepatic inflammation and lead to fibrosis over time. These include FXR agonists, ASBT inhibitors, and PPAR agonists such as bezafibrate and fenofibrate. Nonetheless, many of these drugs can only delay disease progression and fail to enhance patients' quality of life. Nanomedicine shows great potential for treatment of autoimmune diseases, as it provides a new approach that focuses on tolerance induction rather than immunosuppression. Tolerogenic nanoparticles carrying immune-modifying agents can be engineered to safely and effectively target the antigen-specific immune response in autoimmune diseases. These may work well with PBC especially, given the anatomical features and immunological specificity of the disease. Nanobiological therapy is thus an area of highly promising research for future treatment of PBC.

The Role of B Cells and B Cell Therapies in Immune-Mediated Liver Diseases

B cells form a branch of the adaptive immune system, essential for the body’s immune defense against pathogens. B cell dysfunction has been implicated in the pathogenesis of immune mediated liver diseases including autoimmune hepatitis, IgG4-related hepatobiliary disease, primary biliary cholangitis and primary sclerosing cholangitis. B cells may initiate and maintain immune related liver diseases in several ways including the production of autoantibodies and the activation of T cells via antigen presentation or cytokine production. Here we comprehensively review current knowledge on B cell mechanisms in immune mediated liver diseases, exploring disease pathogenesis, B cell therapies, and novel treatment targets. We identify key areas where future research should focus to enable the development of targeted B cell therapies.

An insight into the mechanism and molecular basis of dysfunctional immune response involved in cholestasis

Cholestasis is one of the most common clinical symptom of liver diseases. If patients do not receive effective treatment, cholestasis can evolve into liver fibrosis, cirrhosis and ultimately liver failure requiring liver transplantation. Currently, only ursodeoxycholic acid, obeticholic acid and bezafibrate are FDA-approved drugs, thereby requiring a breakthrough in new mechanisms and therapeutic development. Inflammation is one of the common complications of cholestasis. Hepatic accumulation of toxic hydrophobic bile acids is a highly immunogenic process involving both resident and immigrating immune cells. And the resulting inflammation may further aggravate hepatocyte injury. Though, great investigations have been made in the immune responses during cholestasis, the relationship between immune responses and cholestasis remains unclear. Moreover, scarce reviews summarize the immune responses during cholestasis and the efficacy of therapies on immune response. The main purpose of this paper is to review the existing literature on dysfunctional immune response during cholestasis and the effect of treatment on immune response which may provide an insight for researchers and drug development.

Experimental Pharmacological Agents for the Treatment of Primary Biliary Cholangitis

The standard therapy for primary biliary cholangitis (PBC) is ursodeoxycholic acid (UDCA) which has shown to improve hepatic biochemistry, delay histological progression and improve transplant-free survival. Approximately 30-40% of patients do not respond or are intolerant to UDCA. Obeticholic acid, a farnesoid X receptor (FXR) agonist is the only agent approved by the Food and Drug Administration for patients who do not respond to UDCA. Recently, combination therapy with UDCA and bezafibrate has been shown to improve biochemistry and both GLOBE and UK-PBC score in patients with an inadequate response to UDCA. More recently, new pharmacological agents have been included in Phase 2 and Phase 3 trials: PPAR agonists, non-bile acid FXR agonists, anti-NOX agents, immunomodulators and mesenchymal stem cells transplantation. This review gives an overview on the current experimental pharmacological agents employed in the treatment of PBC.

Primary biliary cholangitis

Primary biliary cholangitis is an autoimmune liver disease that predominantly affects women. It is characterised by a chronic and destructive, small bile duct, granulomatous lymphocytic cholangitis, with typical seroreactivity for antimitochondrial antibodies. Patients have variable risks of progressive ductopenia, cholestasis, and biliary fibrosis. Considerations for the cause of this disease emphasise an interaction of chronic immune damage with biliary epithelial cell responses and encompass complex, poorly understood genetic risks and environmental triggers. Licensed disease-modifying treatment focuses on amelioration of cholestasis, with weight-dosed oral ursodeoxycholic acid. For patients who do not respond sufficiently, or patients with ursodeoxycholic acid intolerance, conditionally licensed add-on therapy is with the FXR (NR1H4) agonist, obeticholic acid. Off-label therapy is recognised as an alternative, notably with the pan-PPAR agonist bezafibrate; clinical trial agents are also under development. Baseline characteristics, such as young age, male sex, and advanced disease, and serum markers of liver injury, particularly bilirubin and ALP, are used to stratify risk and assess treatment responsiveness. Parallel attention to the burden of patient symptoms is paramount, including pruritus and fatigue.

Investigational drugs in early phase development for primary biliary cholangitis

Introduction: With a large percentage of patients having an incomplete response or intolerance to current FDA approved medications, new therapies for the treatment of primary biliary cholangitis are in great demand. Areas covered: In this review, we assess currently available drugs as well as promising new therapies for the treatment of primary biliary cholangitis. A literature search was performed with the following search terms: 'PBC treatment,' 'PBC therapeutics,' 'PBC clinical trials,' and included original articles, meta-analyses, and systematic reviews from 1 January 1981, to 1 January 2020. ClinicalTrials.gov was accessed for data from ongoing trials. Expert opinion: Targeted drug therapies offer an alternative for patients who are unable to meet their therapeutic goals with either of the two currently approved treatment options. Specifically, new drugs targeting bile-acid regulation, immune-modulation, and fibrogenic pathways are currently in development with multiple agents showing encouraging early results with the ultimate goal of developing therapies that will achieve high rates of biochemical remission, will be well tolerated, and improve symptoms and quality of life in patients with primary biliary cholangitis. Based on a review of the current literature, PPAR agonists appear to be promising agents, along with FGF19 analogs and FXR agonists.

Primary biliary cholangitis management: controversies, perspectives and daily practice implications from an expert panel

Primary biliary cholangitis (PBC) is a rare progressive immune-mediated liver disease that, if not adequately treated, may culminate in end-stage disease and need for transplantation. According to current guidelines, PBC is diagnosed in the presence of antimitochondrial antibodies (AMA) or specific antinuclear antibodies, and of a cholestatic biochemical profile, while biopsy is recommended only in selected cases. All patients receive ursodeoxycholic acid (UDCA) in first line; the only registered second-line therapy is obeticholic acid (OCA) for UDCA-inadequate responders. Despite the recent advances in understanding PBC pathogenesis and developing new treatments, many grey areas remain. Six Italian experts selected the following topics as the most urgent to address in PBC management: diagnosis and natural history of PBC: as a portion of the subjects with isolated AMA, normal alkaline phosphatase (ALP) levels and no symptoms of liver disease could have PBC by histology, defining how to manage and follow this population is crucial; role of liver biopsy: recent evidence suggests that biopsy may provide relevant information for risk stratification and prediction of UDCA response, possibly facilitating personalized approaches; risk stratification: the tools for risk stratification are well established, but some issues (eg bile acid dosage in routine practice) remain controversial; and therapy: those in more advanced stages of development are nuclear receptor modulators and fibrates, but more data are needed to plan personalized strategies. In this manuscript, for each topic, current evidence, controversies and future perspectives are summarized with the possible implications for clinical practice.

Th1 Chemokines in Autoimmune Endocrine Disorders

CONTEXT

The CXC chemokine receptor CXCR3 and its chemokines CXCL10, CXCL9, and CXCL11 are implicated in the pathogenesis of autoimmune diseases. Here, we review these chemokines in autoimmune thyroiditis (AT), Graves disease (GD), thyroid eye disease (TED), type 1 diabetes (T1D), and Addison's disease (AAD).

EVIDENCE ACQUISITION

A PubMed review of the literature was conducted, searching for the above-mentioned chemokines in combination with AT, GD, TED, T1D, and AAD.

EVIDENCE SYNTHESIS

Thyroid follicular cells in AT and GD, retroorbital cells in TED (fibroblasts, preadipocytes, myoblasts), β cells and islets in T1D, and adrenal cells in AAD respond to interferon-γ (IFN-γ) stimulation producing large amounts of these chemokines. Furthermore, lymphocytes and peripheral blood mononuclear cells (PBMC) are in part responsible for the secreted Th1 chemokines. In AT, GD, TED, T1D, and AAD, the circulating levels of these chemokines have been shown to be high. Furthermore, these chemokines have been associated with the early phases of the autoimmune response in all the above-mentioned disorders. High levels of these chemokines have been associated also with the "active phase" of the disease in GD, and also in TED. Other studies have shown an association with the severity of hypothyroidism in AD, of hyperthyroidism in GD, with severity of TED, or with fulminant T1D.

CONCLUSION

The reviewed data have shown the importance of the Th1 immune response in different endocrine autoimmune diseases, and many studies have suggested that CXCR3 and its chemokines might be considered as potential targets of new drugs for the treatment of these disorders.

The use of biologics in the treatment of autoimmune liver disease

Introduction: Autoimmune liver diseases include autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and juvenile autoimmune hepatitis (JAIH). The pathophysiologic features of each disease vary, but generally include presence of autoantibodies, cytokine abnormalities, and/or T and B cell autoreactivity.Areas covered: This article compares conventional therapy with newer biologics available for treatment of autoimmune liver diseases. Conventional therapy involves the use of immunosuppressive agents, or other treatment modalities for specific autoimmune liver diseases such as ursodeoxycholic acid and fibrates for PBC. Biologics were developed to target the production of autoantibodies by B cells, the presence of proinflammatory cytokines, adhesion molecules or T and B cell activation.Expert opinion: Despite the promise of biologics being able to target specific cellular and humoral pathways, results have been generally poor, and safety has not been as expected. Cases of autoimmune hepatitis have also developed with the use of these biologicals. Reasons for the lack of success of biologics in treating autoimmune liver disease has led to a reevaluation of our understanding of underlying pathogenesis, demonstrating that while our knowledge of the immunity has improved over the past two decades, it is far from complete.

The challenges of primary biliary cholangitis: What is new and what needs to be done

Primary Biliary Cholangitis (PBC) is an uncommon, chronic, cholangiopathy of autoimmune origin and unknown etiology characterized by positive anti-mitochondrial autoantibodies (AMA), female preponderance and progression to cirrhosis if left untreated. The diagnosis is based on AMA- or PBC-specific anti-nuclear antibody (ANA)-positivity in the presence of a cholestatic biochemical profile, histologic confirmation being mandatory only in seronegative cases. First-line treatment is ursodeoxycholic acid (UDCA), which is effective in preventing disease progression in about two thirds of the patients. The only approved second-line treatment is obeticholic acid. This article summarizes the most relevant conclusions of a meeting held in Lugano, Switzerland, from September 23rd-25th 2018, gathering basic and clinical scientists with various background from around the world to discuss the latest advances in PBC research. The meeting was dedicated to Ian Mackay, pioneer in the field of autoimmune liver diseases. The role of liver histology needs to be reconsidered: liver pathology consistent with PBC in AMA-positive individuals without biochemical cholestasis is increasingly reported, raising the question as to whether biochemical cholestasis is a reliable disease marker for both clinical practice and trials. The urgent need for new biomarkers, including more accurate markers of cholestasis, was also widely discussed during the meeting. Moreover, new insights in interactions of bile acids with biliary epithelia in PBC provide solid evidence of a role for impaired epithelial protection against potentially toxic hydrophobic bile acids, raising the fundamental question as to whether this bile acid-induced epithelial damage is the cause or the consequence of the autoimmune attack to the biliary epithelium. Strategies are needed to identify difficult-to-treat patients at an early disease stage, when new therapeutic approaches targeting immunologic pathways, in addition to bile acid-based therapies, may be effective. In conclusion, using interdisciplinary approaches, groundbreaking advances can be expected before long in respect to our understanding of the etiopathogenesis of PBC, with the ultimate aim of improving its treatment.

Pathobiology of inherited biliary diseases: a roadmap to understand acquired liver diseases

Bile duct epithelial cells, also known as cholangiocytes, regulate the composition of bile and its flow. Acquired, congenital and genetic dysfunctions in these cells give rise to a set of diverse and complex diseases, often of unknown aetiology, called cholangiopathies. New knowledge has been steadily acquired about genetic and congenital cholangiopathies, and this has led to a better understanding of the mechanisms of acquired cholangiopathies. This Review focuses on findings from studies on Alagille syndrome, polycystic liver diseases, fibropolycystic liver diseases (Caroli disease and congenital hepatic fibrosis) and cystic fibrosis-related liver disease. In particular, knowledge on the role of Notch signalling in biliary repair and tubulogenesis has been advanced by work on Alagille syndrome, and investigations in polycystic liver diseases have highlighted the role of primary cilia in biliary pathophysiology and the concept of biliary angiogenic signalling and its role in cyst growth and biliary repair. In fibropolycystic liver disease, research has shown that loss of fibrocystin generates a signalling cascade that increases β-catenin signalling, activates the NOD-, LRR- and pyrin domain-containing 3 inflammasome, and promotes production of IL-1β and other chemokines that attract macrophages and orchestrate the process of pericystic and portal fibrosis, which are the main mechanisms of progression in cholangiopathies. In cystic fibrosis-related liver disease, lack of cystic fibrosis transmembrane conductance regulator increases the sensitivity of epithelial Toll-like receptor 4 that sustains the secretion of nuclear factor-κB-dependent cytokines and peribiliary inflammation in response to gut-derived products, providing a model for primary sclerosing cholangitis. These signalling mechanisms may be targeted therapeutically and they offer a possibility for the development of novel treatments for acquired cholangiopathies.

Emerging novel treatments for autoimmune liver diseases

The etiology of autoimmune liver diseases, such as autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC), still remains largely unknown and no therapeutic agents that are able to "cure" these diseases have been developed. Although corticosteroids for AIH and ursodeoxycholic acid for PBC have been shown to significantly improve liver transplantation (LT)-free survival and are recommended as first-line drugs, treatment strategies for patients who show incomplete response to these drugs have not yet been fully established. No drug is significantly associated with long LT-free survival in PSC patients. Nevertheless, with progress in genetics, immunology, and cellular biology, several new compounds or antibodies are expected to have an effect on autoimmune liver diseases and several drugs are under consideration for clinical use. Although most clinical trials have been carried out in the USA or Europe, some are, or will be, undertaken in Japan in the future. In this review, the current standard-of-care of autoimmune liver diseases will be summarized, together with emerging novel treatments relevant to clinical practice in Japan.

Immunological abnormalities in patients with primary biliary cholangitis

Primary biliary cholangitis (PBC), an autoimmune liver disease occurring predominantly in women, is characterized by high titers of serum anti-mitochondrial antibodies (AMAs) and progressive intrahepatic cholestasis. The immune system plays a critical role in PBC pathogenesis and a variety of immune cell subsets have been shown to infiltrate the portal tract areas of patients with PBC. Amongst the participating immune cells, CD4 T cells are important cytokine-producing cells that foster an inflammatory microenvironment. Specifically, these cells orchestrate activation of other immune cells, including autoreactive effector CD8 T cells that cause biliary epithelial cell (BEC) injury and B cells that produce large quantities of AMAs. Meanwhile, other immune cells, including dendritic cells (DCs), natural killer (NK) cells, NKT cells, monocytes, and macrophages are also important in PBC pathogenesis. Activation of these cells initiates and perpetuates bile duct damage in PBC patients, leading to intrahepatic cholestasis, hepatic damage, liver fibrosis, and eventually cirrhosis or even liver failure. Taken together, the body of accumulated clinical and experimental evidence has enhanced our understanding of the immunopathogenesis of PBC and suggests that immunotherapy may be a promising treatment option. Herein, we summarize current knowledge regarding immunological abnormalities of PBC patients, with emphasis on underlying pathogenic mechanisms. The differential immune response which occurs over decades of disease activity suggests that different therapies may be needed at different stages of disease.

Improvement of pharmacokinetic properties of therapeutic antibodies by antibody engineering

Monoclonal antibodies (mAbs) have become an important therapeutic option for several diseases. Since several mAbs have shown promising efficacy in clinic, the competition to develop mAbs has become severe. In efforts to gain a competitive advantage over other mAbs and provide significant benefits to patients, innovations in antibody engineering have aimed at improving the pharmacokinetic properties of mAbs. Because engineering can provide therapeutics that are more convenient, safer, and more efficacious for patients in several disease areas, it is an attractive approach to provide significant benefits to patients. Further advances in engineering mAbs to modulate their pharmacokinetics were driven by the increase of total soluble target antigen concentration that is often observed after injecting a mAb, which then requires a high dosage to antagonize. To decrease the required dosage, several antibody engineering techniques have been invented that reduce the total concentration of soluble target antigen. Here, we review the various ways that antibody engineering can improve the pharmacokinetic properties of mAbs.